Untitled - D Ank Unlimited

doubling dilution 236 drug-induced autoimmunity
system involvement, low avidity anti-dsDNA autoantibodies
are more common than high avidity anti-dsDNA autoantibodies.
Sera from patients suspected of having SLE should
be assayed for autoantibodies to dsDNA (Farr technique)
and to Sm (enzyme immunoassay with IB confirmation),
as either or both of these autoantibodies are essentially
diagnostic of SLE.
1 volume
serum
1 in 2
(a)
1 volume
saline
1 vol.
A
1 in 4
doubling dilution
A technique used in serology to prepare serial dilutions
of serum. A fixed quantity (one volume) of physiologic
saline is added to each of a row of serological tubes except
for the first tube in the row that receives two volumes of
serum. One volume of serum from the first tube is added to
one volume of saline in the second tube. After thoroughly
mixing the contents with the transfer pipette, one volume
of the second tube is transferred to the third, and the
procedure is repeated down the row. This same volume is
then discarded from the final tube after the contents have
been thoroughly mixed. Thus, the serum dilution in each
tube is double that in the preceding tube. The first tube is
undiluted; the second contains a 1:2 dilution; the third, a
1:4; the fourth, a 1:8, etc.
doughnut structure
The assembly and insertion of complement C9 protein
monomers into a cell membrane to produce a transmembrane
pore that leads to cell destruction through the
cytolytic action of the complement cascade.
DP pause
T cell developmental stage during which TCR α genes
of the earliest double positive (DP) thymocytes are in the
process of TCR α rearrangement on both chromosomes.
For 3 to 4 days, a DP cell synthesizes candidate TCR α
chains and conducts productivity testing with its existing
functional TCRβ chain.
DP thymocytes
Double positive thymocytes that bear both CD4 and CD8
molecules. Thus, their surface phenotype is CD4 + CD8 + .
DPT vaccine
A discontinued immunizing preparation that consisted of
a combination of diphtheria and tetanus toxoids and killed
pertussis microorganisms. It is no longer used in pediatric
immunizations because of the superiority of the DTaP vaccine
that contains only acellular pertussis microorganisms.
(b)
1 vol.
saline
Doubling dilution.
1 vol.
B
1 in 8
(c)
1 vol.
saline
draining lymph node
A lymph node that collects fluid draining through lymphatic
channels from an anatomical site of infection before returning
to the blood circulation.
Drakeol 6VR
A purified light mineral oil employed to prepare water-inoil
emulsion adjuvants.
drift
Refer to antigenic drift.
DRiP pathway
Defective ribosomal products pathway. A form of antigen
processing whereby misfolded polypeptides are ubiquinated
rapidly and digested by standard proteasomes, rendering the
resulting DRiP peptides capable of association with MHC
class I molecules.
drug allergy
An immunopathologic or hypersensitivity reaction to a
drug. Some drugs are notorious for acting as haptens that
bind to proteins in the skin or other tissues that act as
carriers. This hapten–carrier complex elicits an immune
response manifested as either antibodies or T lymphocytes.
Any of the four types of hypersensitivity in the Coombs and
Gell classification may be mediated by drug allergy. One
of the best known allergies is hypersensitivity to penicillin.
Antibodies to a drug linked to carrier molecules in the host
may occur in autoimmune hemolytic anemia or thrombocytopenia,
anaphylaxis, urticaria, and serum sickness. Skin
eruptions are frequent manifestations of a T cell-mediated
drug allergy.
Drug
RBC
c
Hemolysis
C
RBC
Drug-induced hemolysis.
drug-induced autoimmunity
Some mechanisms in drug-induced autoimmunity are
similar to those induced by viruses. Autoantibodies may
appear as a result of the helper determinant effect. With
some drugs such as hydantoin, the mechanism resembles
that of the Epstein–Barr virus (EBV). The generalized
lymphoid hyperplasia also involves clones specific for
autoantigens. A third form is that seen with α-methyldopa.
This drug induces the production of specific antibodies. The
drug attaches to cells in vivo without changing the surface
antigenic makeup. The antibodies, which often have anti-e
(Rh series) specificity, combine with the drug on cells, fix
complement, and induce a bystander type of complementmediated
lysis. Another form of drug-induced autoimmunity
c
C
C
C